Yup... It's a DC power plug jack. Exciting stuff.
As we all know, 'DC' stands for 'Dangerous Cantaloupe', 'Doubly Cool' and above all else, 'Dang, Caterpillar!". In some rarer cases it also stands for 'Direct Current', which has something to do with electricity, we presume. This is a standard DC-style female plug, that comes as the connector itself plus a screw-on plastic casing.
Look, some specifications!
Plug/Mating Plug Diameter: 2.1mm ID, 5.5mm OD
Number of Positions/Contacts: 2 Conductors, 2 Contacts
Mounting Type: Free Hanging (In-Line)
Contact Material: Brass, Plating Nickel
Housing Material: Thermoplastic
Operating Temperature: 0°C ~ 40°C
Voltage - Rated: 24VDC
Current Rating: 5A